The Coast Guard is conducting search and rescue flights across the devastated Gulf Coast.

The Coast Guard is also assessing damage and working to make sure ports can reopen.

President Joe Biden is set to hold a virtual meeting Monday afternoon with FEMA and leaders from areas impacted by Ida.

AT&T said its Louisiana wireless network is operating at 60%.

"We had key network facilities go offline overnight, and while some have already been restored, some facilities remain down and are inaccessible due to flooding and storm damage," AT&T said in a statement.

-ABC News' Alexandra Faul

New Orleans residents who evacuated their homes should not return until further notice, the New Orleans Office of Homeland Security and Emergency Preparedness said.

"There is widespread debris, power remains out, and emergency services are working to respond to those still in the city," city officials said. "We will let you know when it is safe to come home."

The Louis Armstrong New Orleans International Airport is conducting damage assessments and said it expects all flights to be canceled Monday.

The airport added that passengers should check directly with their airlines for more information.

So far New Orleans' airport has 118 canceled flights. Some flights have also been canceled in Houston, Dallas, Pensacola and Atlanta.

-ABC News' Alexandra Faul, Amanda Maile

Louisiana Gov. John Bel Edwards provided another update on the damage from Hurricane Ida Monday evening.

Edwards said the state is still in a search and rescue mode as torrential rain and strong winds from the tropical depression continue to hit the state.

He said the entire southeastern section of the state is without power and over 1 million people are affected.

"There are an awful lot of unknowns right now," Edwards said. "I can't tell you when the power is going to be restored."

Edwards said the priority is to restore electricity to critical infrastructure and services, such as hospitals and dialysis centers.

Three hospitals were evacuated and a fourth is in the process of moving their patients, according to the governor.

Edwards said there was a "silver lining" from the storm in that there have been no reports of breached levees. There may have been a few levees where water overflowed, but the levees held up in critical locations, including New Orleans, according to the governor.

"They did not fail," he said.

Edwards urged homeowners who evacuated to not return to their homes until their parish leaders give the all-clear.

The Louisiana National Guard rescued 191 citizens and 27 pets so far across Jefferson, St. John the Baptist and Orleans parishes, Edwards said. They are conducting more sweeps through the affected areas.

The governor urged homeowners in affected areas to stay safe, as most hurricane fatalities take place long after the storm hits. He reminded people to use generators outside their houses, avoid driving through deep waters and not exert themselves during cleanups.

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Edwards did warn that he expects the death toll to rise, but said the numbers won't be as high if people heed warnings.

"This is a tough blow, but things are going to be OK," he said.